Browse Prior Art Database

Fusably Linked Gate Electrodes for Redundant Field Effect Transistors

IP.com Disclosure Number: IPCOM000079748D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Hornung, A: AUTHOR [+2]

Abstract

Field-effect transistor (FET) gate shorts cause significant yield and reliability problems which can be neutralized by the provision of redundant FETs (surplus paralleled FETs) having gate electrodes, which are fusably linked to a common input terminal. More than one FET, such as the three shown in the drawing, are connected in parallel, i.e., all sources being connected together and all drains being connected together. The gate electrodes are made through respective fusable links. In the given example, one of the FETs is required for the operation of a given desired circuit. The other two FETs are redundant devices.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Fusably Linked Gate Electrodes for Redundant Field Effect Transistors

Field-effect transistor (FET) gate shorts cause significant yield and reliability problems which can be neutralized by the provision of redundant FETs (surplus paralleled FETs) having gate electrodes, which are fusably linked to a common input terminal. More than one FET, such as the three shown in the drawing, are connected in parallel, i.e., all sources being connected together and all drains being connected together. The gate electrodes are made through respective fusable links. In the given example, one of the FETs is required for the operation of a given desired circuit. The other two FETs are redundant devices.

Should a gate short occur at any time, the fusable link in series with the shorted FET overloads and becomes open circuited, thereby removing the shorted device from the overall circuit. The remaining paralleled devices insure continued proper circuit performance.

A gate short is typically several thousand ohms or less, and draws about 1 milliampere or more current from an FET gate signal driving source. Accordingly, a metal stripe of approximately 1,000 Angstroms x 1,000 Angstroms cross section becomes fused (open circuited) at about 1 milliampere current and is suitable for use as the fusable links. Stripes of such cross section can be fabricated using electron-beam lithography.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]